Opposed piston two-stroke cycle internal combustion engines

ABSTRACT

A multi-cylinder, opposed piston, two-stroke cycle internal combustion engine, of the kind in which air is admitted to the cylinders under pressure through ports in the cylinder walls at or near the lower ends thereof (i.e. the ends nearest the crankshaft), and exhausted through ports in the cylinder walls at the other ends of the cylinders, has two exhaust driven turbochargers. The gases are exhausted from each cylinder through two sets of ports, the one set of ports for each cylinder being linked to one turbocharger and the other sets to the other turbocharger, so that each turbocharger is driven by approximately half the exhaust gases leaving the engine.

United States Paten [19] Butler et al.

[ 1 May 22,1973

[54] OPPOSED PISTON TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINES [73] Assignee: Doxtord and Sunderland Limited,

Sunderland, England [22] Filed: June 18, 1971 [21] Appl. No.: 154,503

[30] Foreign Application Priority Data June 19, 1970 Great Britain ..29,951/70 [5 6] References Cited UNITED STATES PATENTS 9/1969 Tryhom ..123/l19 CB 8/1962 Jackson et a1 ..60/13 3,093,959 6/1963 Birmann ..60/13 2,979,887 4/1961 Homola et al 3 ,426,736 2/1969 Tryhorn 2,306,277 12/1942 Oswald 2,359,615 10/1944 Browne et al.

Primary Examiner--Laurence M. Goodridge Assistant Examiner-Cort Flint Attorney- Eugene F. Buel, Walter J. Blenko, Jr., and Frederick B. Ziesenheim [57] ABSTRACT A multi-cy1inder, opposed piston, two-stroke cycle internal combustion engine, of the kind in which air is admitted to the cylinders under pressure through ports in the cylinder walls at or near the lower ends thereof (i.e. the ends nearest the crankshaft), and exhausted through ports in the cylinder walls at the other ends of the cylinders, has two exhaust driven turbochargers. The gases are exhausted from each cylinder through two sets of ports, the one set of ports for each cylinder being linked to one turbocharger and the other sets to the other turbocharger, so that each turbocharger is driven by approximately half the exhaust gases leaving the engine. 1

3 Claims, 3 Drawing Figures PATENTEB HLY 2 2 I975 SHEET 1 BF 2 OPPOSED PISTON TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINES The invention relates to opposed piston two-stroke cycle internal combustion engines of the kind in which the pistons are operatively connected to separate cranks on a single crank-shaft and in which air for scavenging and combustion is admitted under pressure to the engine cylinder through ports in the cylinder wall at or near one end thereof (usually the lower end, i.e. the end nearer to the crank-shaft) and the exhaust taking place through ports in the cylinder wall at or adjacent the other end thereof. Such engines will hereinafter be referred to as engines of the kind described.

In such engines the air ports are exposed and covered by one of the pistons during movement thereof and the admission of air to the cylinder is controlled thereby and the exhaust ports are exposed and covered by the other opposed piston which controls the escape of the exhaust gases.

The invention provides a multi-cylinder in line engine of the kind described having a first exhaust driven turbocharger at one end of the engine, and a second exhaust driven turbocharger at the other end of the engine, the first turbocharger being driven by exhaust gases leaving the cylinders from one side of the engine, and the second turbocharger being driven by exhaust gases leaving the cylinders from the other side of the engine.

Preferably each cylinder is surrounded by an exhaust manifold arranged to direct exhaust gases issuing from the exhaust ports at the said one side of the engine to wards the said one end of the engine, and arranged to direct exhaust gases issuing from the exhaust ports at the said other side of the engine towards the said other end of the engine.

By way of example, a specific embodiment of the invention will now be described, with reference to the accompanying drawings, in which:

FIG. 1 shows a plan view of an engine according to the invention;

FIG. 2 shows a horizontal section through a cylinder and exhaust manifold, looking from below the engine, and

FIG. 3 shows a vertical section along line BCD of FIG. 2.

FIG. 1 shows a six-cylinder in line two-stroke cycle opposed piston engine (for example of the kind described in British Patent specification No. 580704) having three compressor 20, 21 and 22 driven from the three end cylinders. The engine is provided with two turbo-blowers 26 and 27 which are driven by the exhaust gases. Turbo-blower 26 is driven by exhaust gases leaving the cylinders from side of the engine, and turbo-blower 27 is driven by exhaust gases leaving the cylinders from side 11 of the engine.

Each cylinder is provided with an exhaust manifold or belt which directs the exhaust gas leaving the cylinder at side 10 of the engine into pipe 28, and directs the exhaust gas leaving the cylinder at side 11 of the engine into pipe 29. The arrangement makes it possible to utilize large area exhaust ports and obtain a relatively free flow of gas to the exhaust pipes 28, 29 and turbochargers 26, 27. Each cylinder as it exhausts at high velocity tends to produce an extractor effect on other cylinders which may be just starting, or building up, their exhaust phase.

Air from the turbo-blowers is delivered via pipes 30, 32 to manifold 31 which acts as an air reservoir and supplies the compressors 20, 21 and 22.

One example of exhaust belt is shown in FIG. 2. The associated cylinder 1 houses a piston 7 and has exhaust ports 2. Surrounding the cylinder in the region of the exhaust ports is an exhaust belt 3. The belt defined gas passageways 5, 6. The passageways 5 at one side of the cylinder are arranged to direct exhaust gases towards pipe 28 in the direction of turbo-blower 26, and passageways 6 at the other side of the cylinder are arranged to direct exhaust gases towards pipe 29 in the direction of turbo-blower 27. The belt 3 takes advantage of the direction of swirl of gases leaving the cylinder (clockwise as viewed from above the engine). Since the swirl is tending to direct the exhaust gases in the directions defined by passageways, the flow of gases down the passageways is facilitated.

FIG. 3 shows how the height of one of the passageways 6 varies. The passageways are substantially rectangular in section, the height of "the passageways increasing in the radial direction.

The invention is not restricted to the features of the foregoing embodiment.

We claim:

1. A multi-cylinder in lien, opposed piston, two stroke cycle, internal combustion engine of the kind in which the pistons are operatively connected to separate cranks on a single crank-shaft and in which air for scavenging and combustion is admitted under pressure to the engine cyclinder through ports in the cylinder wall in the region of one end thereof, the exhaust taking place through ports in the cylinder wall in the region of the other end thereof, and having a first exhaust driven turbocharger at one end of the engine, and a second exhaust driven turbocharger at the other end of the engine, the first tdrbocharger having passageways directing exhaust gases from the exhaust ports on one side of each cylinder of the engine through a common manifold line to said first turbocharger, and the second turbocharger having passageways directing exhaust gases from the the exhaust ports on the other side of each cylinder of the engine through a common manifold to said second turbocharger.

2. An engine as claimed in claim 1 in which each cylinder is surrounded by an exhaust manifold arranged to direct exhaust gases issuing from the exhaust ports at the said one side of the engine towards the said one end of the engine, and arranged to direct exhaust gases issuing from the exhaust ports at the said other side of the engine towards the said other end of the engine.

3. An engine as claimed in claim 2 in which there are provided six cylinders and twelve pistons in said cylinders, air being admitted to each cylinder in the region of the end nearer the crankshaft, in which the turbochargers supply air to compressors which in turn supply air to the cylinders, and in which each cylinder is provided with four exhaust ports, two such ports being linked to each turbocharger by rectangular passageways and by exhaust manifolds, the said ports, passageways and exhaust manifolds being arranged to direct the flow of exhaust gas in the same sense as the direction of swirl of the gas in the cylinder, and the passageways increasing in height in the radial direction. 

1. A multi-cylinder in lien, opposed piston, two stroke cycle, internal combustion engine of the kind in which the pistons are operatively connected to separate cranks on a single crank-shaft and in which air for scavenging and combustion is admitted under pressure to the engine cyclinder through ports in the cylinder wall in the region of one end thereof, the exhaust taking place through ports in the cylinder wall in the region of the other end thereof, and having a first exhaust driven turbocharger at one end of the engine, and a second exhaust driven turbocharger at the other end of the engine, the first turbocharger having passageways directing exhaust gases from the exhaust ports on one side of each cylinder of the engine through a common manifold line to said first turbocharger, and the second turbocharger having passageways directing exhaust gases from the the exhaust ports on the other side of each cylinder of the engine through a common manifold to said second turbocharger.
 2. An engine as claimed in claim 1 in which each cylinder is surrounded by an exhaust manifold arranged to direct exhaust gases issuing from the exhaust ports at the said one side of the engine towards the said one end of the engine, and arranged to direct exhaust gases issuing from the exhaust ports at the said other side of the engine towards the said other end of the engine.
 3. An engine as claimed in claim 2 in which there are provided six cylinders and twelve pistons in said cylinders, air being admitted to each cylinder in the region of the end nearer the crankshaft, in which the turbochargers supply air to compressors which in turn supply air to the cylinders, and in which each cylinder is provided with four exhaust ports, two such ports being linked to each turbocharger by rectangular passageways and by exhaust manifolds, the said ports, passageways and exhaust manifolds being arranged to direct the flow of exhaust gas in the same sense as the direction of swirl of the gas in the cylinder, and the passageways increasing in height in the radial direction. 